Sometimes it is useful to refer to a specific changeset or review using a permalink, either from within Review Board or from external applications (as also requested in https://hellosplat.com/s/beanbag/tickets/4398/ ). I noticed that the templates do already contain anchors for these items, there just isn't an easy way to obtain links to them (aside from inspecting the DOM). This change makes the posted_time-elements for changes and reviews permalinks to these items.

Clicked through the application. Permalinks work; nothing else seems to be broken.